1. Field of the Invention
This invention relates to an electronic musical instrument, and more particularly to an electronic musical instrument provided with portamento function.
In this specification, "portamento" means continuous or gradual change in the pitch of generated musical sound, and includes slur.
2. Description of the Related Art
In performance of a musical instrument, portamento play may sometimes be desired, in which the pitch of the musical sound continuously changes from one pitch to another pitch.
In an electronic musical instrument of the keyboard type, a portamento bar for assigning a continuously changing pitch sound may be provided besides a keyboard which is used for generating scale sounds. By manipulating the portamento bar, a portamento sound which changes the pitch continuously can be generated, in addition to the ordinary performance in the keyboard for generating scale sounds.
For example, Japanese Utility Model Publication No. Sho. 41-11968 discloses an example of a portamento system which can be applied to a keyboard instrument such as an organ. FIG. 9 reproduces this structure. A portamento system 61 having an oscillator system installed therein is detachably attached to a host instrument 65 in front of a keyboard 60. A sliding terminal 64 for achieving portamento performance may be slid over a resistance element 63 which constitutes an oscillation circuitry to continuously change the resistance and hence to continuously change the oscillation frequency of the oscillator. Thus, a portamento sound having a continuously changing pitch can be generated from the oscillator, in response to the movement of the sliding terminal 64. In this way, by adding a portamento system to an ordinary keyboard instrument, it is made possible to achieve such a performance in which while the left hand plays the keyboard to generate a chord sound, the right handplays the sliding terminal of the portamento system to generate the melody in a portamento sound.